Egyptian officials say a group of tourists was in a "restricted" area when security forces opened fire on Sunday, mistaking the group for suspected terrorists and killing at least 12 people, including two Mexican citizens.

Egypt's Ministry of Foreign Affairs said Monday that military and police forces were "targeting terrorists utilizing four-by-four vehicles similar to those being used by the tourists" when they fired on the visitors Sunday in Farafra, part of Egypt's western desert.

Six survivors told Mexico's ambassador to Egypt that their convoy was attacked by plane and helicopter.

Mexico condemns killing

Mexican President Enrique Pena Nieto has demanded an investigation into the deadly shooting in which several Egyptians were also killed.

"Mexico condemns the acts against our citizens and has demanded from the Egyptian government an exhaustive investigation into what happened," he wrote late Sunday on Twitter.

No proper permits

Rasha Azazi, a spokesperson for the Egyptian Ministry of Tourism, said the involved tour company did not have the proper permits and did not inform authorities that tourists would be in the area. He told the Associated Press that all trips to Farafra have to be cleared by authorities.

Another ten people were wounded in the shooting, including at least six Mexicans who were hospitalized near Cairo.